PPEM 405 Microbe-Plant Interactions (3 credits)

Microbe-Plant Interactions: Plant Disease and Biological Control 3 credits (two lectures and one lab per week)

Course Logistics

Lecture: M/F 2:30-3:20 p.m. Room 215 Thomas Building
Lab Sec 001: W 12:20-2:10 p.m. Room 201 Buckhout Lab
Lab Sec 002: W 2:30-4:20 p.m. Room 201 Buckhout Lab

Instructor: Cristina Rosa, Asst. Prof. Plant Virology
Office location: 321 Buckhout Lab
Office phone number: 814-867-5372

Lab Assistant: Matthew Wheatley

Office Hours: individually by appointment, in groups as organized by T.A. during semester.

Prerequisite: BIOL 110. BIOL 230W is recommended but not required. This course is designed for Junior/Senior undergraduates and beginning graduate students. Students are expected to have a basic understanding of plant and cell biology and basic genetics.

Course Description

Developing new strategies for maintaining healthy plants requires understanding of pathogen and host biology, as well as an understanding of the role of the environment in disease epidemiology. The survival and spread of plant-associated fungi, bacteria, nematodes, and viruses will be studied under different climatic, political, and sociological systems. The mechanisms for microbial pathogenicity and their impact on food production around the globe will form the basis of this course. Plant disease management in the United States and other countries and the use of beneficial microorganisms for biological control will be discussed and developed. The course meets the International Agriculture and Development (INTAD) dual-title graduate degree program and International Agriculture (INTAG) undergraduate minor requirements, since it describes global systems that affect world food production. Students will apply research, extension, education, and evaluation tools for both collaborative development and technology transfer/adaptation, especially in resource-poor situations.

Course Objectives

In this course, you will:

  1. identify basic characteristics of the major groups of pathogenic microorganisms, fungi, bacteria, viruses, and of nematodes;
  2. Evaluate the effects of environmental conditions on plant diseases under different climates;
  3. Apply basic plant pathology concepts to design plant health management strategies across the globe;
  4. Discuss plant diseases impacts on global trade and production.

Objectives 2-4 satisfy the INTAD Student Learning Objective 1. Objective 4 satisfies the INTAD Student Learning Objective 4. The course satisfies two INTAG categories: Animal and Plant Science and Natural Resource and Environment.

Recommended Textbook

Plant Pathology. 2005. G.N. Agrios, Elsevier Academic Press. Additional readings on global impacts will be provided in class.

Evaluation and Grading

This course was developed following a revised Bloom’s taxonomy (1956) with activities structured on six levels of thinking: remembering, understanding, applying, analyzing, evaluating, and creating (Anderson 2001). These levels will be approached sequentially and will be often reiterated. Each level will be assessed by the instructor as well as by your peers sitting in your same class.

The methods of course delivery will be through instructional lectures and by student-centered activities.

AssessmentPointsGrade %
Four exams (150 pts each) 600 60%
Lab participation and reports: 14.6 pts x 15 weeks 220 22%
Resource-poor country extension activity 80 8%
Lab practical 80 8%
Global impact assignment (video) 20 2%
TOTAL 1,000 100%

Class Attendance

Experience indicates that poor attendance in lecture and other class activities is directly related to poor performance on exams. Exams are based on information obtained from lectures, discussions, and assigned readings. Often lecture and discussion information is not covered in the textbook.

Lab Participation and Reports

Participation in in-class activities will be rewarded, together with weekly reports. Team work as well as individual participation will be required and in-class feedback will be expected. All lab reports must be typed and are due the Friday following the attended lab session. An example of the lab report will be distributed during the first week of class.

Exam Policy

Exams are scheduled during class times. Make-up exams will be allowed only if the student has a valid excuse from his or her academic adviser or doctor. Make-up exams will be given during the first class period attended by the student after his or her absence and will be scheduled only for students with valid reasons. Students missing an exam without a valid excuse will receive a grade of zero for that exam and will not have the chance to take make-up exams. Unusual circumstances affecting exams must be discussed with the instructor prior to the scheduled exam.

Global Impact Assignment/Outline

The assignment must be focused on a global plant pathology problem of current interest. General topics will be assigned by the instructor and specific topics must be approved by the instructor. The assignment Outline will reference at least five peer-reviewed citations (ex. Phytopathology, Plant Disease, etc…) and will be graded separately. Additional references (textbooks, trade magazines, websites, etc.) may be used but will not count towards the five-journal minimum. Each team will prepare a two-minute presentation (video clip) on their assignment. Video aid is available through the library. Presentations will be graded based on subject knowledge, organization, visual aids, and professionalism (both verbal and non-verbal presentation). The best video clips will be uploaded on the class website.

Resource-Poor Country Extension Activity

A plant pathology based strategy to manage a plant disease in a resource-poor country will be developed by students and presented in a smart phone app format.

Lecture Schedule

This schedule is tentative; the instructor will inform you of any changes.




1 Aug 22 Intro to Plant Pathology Quiz/introductory lecture
2 Aug 24 Disease symptomatology/ Plant Disease Clinic tour Samples from field/serial dilution/ Microscopes/Pipettes
3 Aug 26 Plant health and microbes Quiz/understanding symptomatology
Weekly objectives: Understanding what is plant pathology and role of microbes in plant diseases



4 Aug 29 Introduction to Plant Virology Quiz
5 Aug 31 Virus Transmission/ Koch's Postulates Mechanical/Vector inoculation
6 Sept 2 +ssRNA viruses/Potyviruses Diseases caused by Potyviruses
Weekly objectives: Understanding disease cycles and fundamentals of plant virology



7 Sept 5 Holiday/No class Holiday/No class
8 Sept 7

Identification of unknown viruses/ iMovies training

ELISA; library training (meet at library room W140)
9 Sept 9 -ssRNA viruses / Tospoviruses Diseases caused by Tospoviruses
Weekly objectives: Economic importance of viral diseases in agriculture



10 Sept 12 dsRNA viruses Badnaviruses Diseases caused by Badnaviruses
11 Sept 14 Global impact assignment In-class activity
12 Sept 16 Midterm 1 In-class midterm
Weekly objectives: Viral diseases in the tropics



13 Sept 19 Introduction to bacterial diseases Fundamentals of bacteriology
14 Sept 21 A look at bacterial diseases Isolation
15 Sept 23 Epidemiology and mgt of bacterial diseases Epidemiology and disease mgt
Weekly objectives: Understanding bacterial diseases



16 Sept 26 Bacterial diseases Case studies I
17 Sept 28 Fire blight Fire blight lab
18 Sept 30 Bacterial diseases Case studies II
Weekly objectives: Application of theoretical concepts to case studies



19 Oct 3 Introduction to Nematology Cyst nematodes
20 Oct 5 Nematodes/nematodes as viral vectors Observe nematodes
21 Oct 7 Weapons of pathogens In-class lecture and activities
Weekly objectives: Economic importance of nematodes, fundamentals of pathogenicity



22 Oct 10 Ascomycetes/Alternaria Fundamentals of mycology
23 Oct 12 Lab practical Lab practical
24 Oct 14 Midterm 2 In-class midterm
Weekly objectives: Become familiar with fungi



25 Oct 17 Ascomycetes Taphrina/Monilinia In-class lecture and activities
26 Oct 19 Fungi survival structures Media selection
27 Oct 21 Defense through genetically engineering In-class lecture and activities
Weekly objectives: Fundamentals of biotechnology



28 Oct 24 Rusts/smuts *In-class lecture and activities
29 Oct 26 Fungi survival structures cont. *Media selection continuation
30 Oct 28 Chemical control *In-class lecture and activities
Weekly objectives: Lifestyle of rusts/fungi resilience



31 Oct 31 Basidiomycetes Lecture and in-class activities
32 Nov 2 Mushroom cultivation Compost Inoculation
33 Nov 4 Economic impact of plant pathology In-class activities
Weekly objectives: Introduction to mushroom cultivation



34 Nov 7 Oomycetes/Phytophtora/Plasmopora viticola Lecture and in-class activities
35 Nov 9 Mushroom cultivation/virulence assays Observations on compost
36 Nov 11 Midterm 3 In-class midterm
Weekly objectives: Understanding oomycetes



37 Nov 14 Plant defenses Lecture
38 Nov 16 Virulence assays cont. Work of a plant pathologist
39 Nov 18 Plant defenses cont. In-class activities
Weekly objectives: Understanding coevolution and fundamentals of chemical ecology



40 Nov 21 Holiday/No Class  Holiday/No Class
41 Nov 23  Holiday/No Class  Holiday/No Class
42 Nov 25  Holiday/No Class  Holiday/No Class



43 Nov 28 Epidemics  Polycyclic vs monocyclic diseases Work on extension activities
44 Nov 30 Presentations Presentations
45 Dec 2 Modeling of plant disease epidemics Class assessment: extension
Weekly objectives: Understanding disease epidemics



46 Dec 5 Plant Pathogen Diagnostics Work on global impact
47 Dec 7 Videos Video presentations
48 Dec 9 Disease management IPM In-class activities and lecture
Weekly objectives: Fundamentals of integrated pest management
17 Dec 12-16 Final exam Final comprehensive exam

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